| abstract |
(57) [Problem] There is a problem that an Internet telephone adapter connected to a conventional telephone cannot switch to a public line when an Internet telephone is not available and make a telephone call as a normal telephone. SOLUTION: A communication device adapter connecting a public line and an IP network is provided with a public line signal transmitting / receiving means 110. 0 inputs the call information and the telephone number from the telephone 10, the connection destination determining means 200 acquires the IP address corresponding to the telephone number, generates the route selection information, and sends the route selection information to the line connection switching means 100. hand over. Line connection switching means 10 0 selects one of the route of the public line 13 and the route via the IP network 14 from the IP network communication processing means 5000 according to the route selection information, The call information is transmitted to the telephone 20. |